1. Field of the Invention
The present invention relates to a data recording apparatus and a data recording method, and more particularly relates to a data recording apparatus driven by a power supply having a limited driving time period such as a battery, and a data recording method applied to the data recording apparatus.
2. Description of the Related Art
Conventionally, there have been commercially available on the market data recording apparatuses such as an electronic camera which uses a memory card including a solid state memory device as a recording medium, and records video and audio on the recording medium. These data recording apparatuses temporarily stores still image data and moving image data acquired by an image pickup device and audio data acquired by an audio recording device on a volatile memory (write buffer), and then transfer these data to the recording medium.
If data which have not been transferred to the recording media still remain on the write buffer when the battery becomes empty, the data will be lost. To prevent this, conventionally the image pickup operation is not carried out until the battery becomes completely empty, but the data acquisition is terminated when the residual battery capacity decreases below a predetermined capacity (Japanese Laid-Open Patent Publication (Kokai) No. H06-165011, for example).
However, according to the conventional data recording apparatus, once the data acquisition is terminated, it is no longer possible to acquire data at all even if the battery capacity is still sufficient. Therefore, it has been desired that data can be acquired to the maximum possible extent without the already acquired data being lost when the battery capacity is still sufficient.